README

= Validatable
Validatable is a library for adding validations.
by Jay[http://jayfields.blogspot.com] Fields[http://jayfields.blogspot.com]
== Download and Installation
You can download Validatable from here[http://rubyforge.org/projects/validatable] or install it with the following command.
$ gem install validatable
== License
You may use, copy and redistribute this library under the same terms as Ruby itself (see http://www.ruby-lang.org/en/LICENSE.txt).
== Examples
Validation of an entire hierarchy of objects with errors aggregated at the root object.
class Person
include Validatable
validates_presence_of :name
attr_accessor :name
end
class PersonPresenter
include Validatable
include_validations_for :person
attr_accessor :person
def initialize(person)
@person = person
end
end
presenter = PersonPresenter.new(Person.new)
presenter.valid? #=> false
presenter.errors.on(:name) #=> "can't be blank"
Validations that turn off after X times of failed attempts.
class Person
include Validatable
validates_presence_of :name, :times => 1
attr_accessor :name
end
person = Person.new
person.valid? #=> false
person.valid? #=> true
Validations can be given levels. If a validation fails on a level the validations for subsequent levels will not be executed.
class Person
include Validatable
validates_presence_of :name, :level => 1, :message => "name message"
validates_presence_of :address, :level => 2
attr_accessor :name, :address
end
person = Person.new
person.valid? #=> false
person.errors.on(:name) #=> "name message"
person.errors.on(:address) #=> nil
Validations can also be given groups. Groups can be used to validate an object when it can be valid in various states. For example a mortgage application may be valid for saving (saving a partial application), but that same mortgage application would not be valid for underwriting. In our example a application can be saved as long as a Social Security Number is present; however, an application can not be underwritten unless the name attribute contains a value.
class MortgageApplication
include Validatable
validates_presence_of :ssn, :groups => [:saving, :underwriting]
validates_presence_of :name, :groups => :underwriting
attr_accessor :name, :ssn
end
application = MortgageApplication.new
application.ssn = 377990118
application.valid_for_saving? #=> true
application.valid_for_underwriting? #=> false
As you can see, you can use an array if the validation needs to be part of various groups. However, if the validation only applies to one group you can simply use a symbol for the group name.
Similar to Rails, Validatable also supports conditional validation.
class Person
include Validatable
attr_accessor :name
validates_format_of :name, :with => /.+/, :if => Proc.new { !name.nil? }
end
Person.new.valid? #=> true
Validatable also exposes an after_validate hook method.
class Person
include Validatable
validates_presence_of :name
attr_accessor :name
end
class ValidatesPresenceOf
after_validate do |result, instance, attribute|
instance.errors.add("#{attribute} can't be blank") unless result
end
end
person = Person.new
person.valid? #=> false
person.errors.on(:name) #=> "name can't be blank"
The after_validate hook yields the result of the validation being run,
the instance the validation was run on, and the attribute that was validated
In the above example the attribute "name" is appended to the message.
See the tests for more examples
== Contributors
Rick Bradley, Anonymous Z, Jason Miller, Ali Aghareza, Xavier Shay, Dan Manges, Karthik Krishnan and Venkat, Clint Bishop